In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy-Bickford beams (RBBs) and those of the corresponding homogenous Euler-Bernoulli beams are...In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy-Bickford beams (RBBs) and those of the corresponding homogenous Euler-Bernoulli beams are presented. The effective material properties of the FGM beams are assumed to vary continuously in the thickness direction. Governing equations for the titled problem are formulated via the principle of virtual displacements based on the third-order shear deformation beam theory, in which the higher-order shear force and bending moment are included. General solutions of the displacements and the stress resultants of the FGM RBBs are derived analytically in terms of the deflection of the reference homogenous Euler- Bernoulli beam with the same geometry, loadings and end conditions, which realize a classical and homogenized expression of the bending response of the shear deformable non-homogeneous FGM beams. Particular solutions for the FGM RBBs under specified end constraints and load conditions are given to validate the theory and methodology. The key merit of this work is to be capable of obtaining the high-accuracy solutions of thick FGM beams in terms of the classical beam theory solutions without dealing with the solution of the complicated coupling differential equations with boundary conditions of the problem.展开更多
AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore t...AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore the pertinent test methods. METHODS: A systematic analysis of 30 probands from HNPCC families in the north of China was performed by immunohistochemistry, microsatellite instability (MSI), gene mutation and methylation detection. RESULTS: High frequency microsatellite instability occurred in 25 probands (83.3%) of HNPCC family. Loss of hMLH1 and hMSH2 protein expression accounted for 88% of all microsatellite instability. Pathogenic muta-tion occurred in 14 samples and 3 novel mutational sites were discovered. Deletion of exons 1-6, 1-7 and 8 of hMSH2 was detected in 3 samples and no large fragment deletion was found in hMLH1. Of the 30 probands, hMLH1 gene promoter methylation occurred in 3 probands. The rate of gene micromutation detection combined with large fragment deletion detection was 46.7%-56.7%. The rate of the two methods in combination with methylation detection was 63.3%. CONCLUSION: Scientific and rational detection strategy can improve the detection rate of HNPCC. Based on traditional molecular genetics and combined with epigenetics, multiple detection methods can accurately diagnose HNPCC.展开更多
Piao chicken,a rare Chinese native poultry breed,lacks primary tail structures,such as pygostyle,caudal vertebra,uropygial gland,and tail feathers.So far,the molecular mechanisms underlying tail absence in this breed ...Piao chicken,a rare Chinese native poultry breed,lacks primary tail structures,such as pygostyle,caudal vertebra,uropygial gland,and tail feathers.So far,the molecular mechanisms underlying tail absence in this breed remain unclear.In this study,we comprehensively employed comparative transcriptomic and genomic analyses to unravel potential genetic underpinnings of rumplessness in Piao chicken.Our results reveal many biological factors involved in tail development and several genomic regions under strong positive selection in this breed.These regions contain candidate genes associated with rumplessness,including Irx4,Il18,Hspb2,and Cryab.Retrieval of quantitative trait loci(QTL)and gene functions implies that rumplessness might be consciously or unconsciously selected along with the high-yield traits in Piao chicken.We hypothesize that strong selection pressures on regulatory elements might lead to changes in gene activity in mesenchymal stem cells of the tail bud.The ectopic activity could eventually result in tail truncation by impeding differentiation and proliferation of the stem cells.Our study provides fundamental insights into early initiation and genetic basis of the rumpless phenotype in Piao chicken.展开更多
基金supported by the National Natural Science Foundation of China with Grant Numbers 11272278 and 11672260.The authors gratefully acknowledge the financial supports.
文摘In this paper, correspondence relations between the solutions of the static bending of functionally graded material (FGM) Reddy-Bickford beams (RBBs) and those of the corresponding homogenous Euler-Bernoulli beams are presented. The effective material properties of the FGM beams are assumed to vary continuously in the thickness direction. Governing equations for the titled problem are formulated via the principle of virtual displacements based on the third-order shear deformation beam theory, in which the higher-order shear force and bending moment are included. General solutions of the displacements and the stress resultants of the FGM RBBs are derived analytically in terms of the deflection of the reference homogenous Euler- Bernoulli beam with the same geometry, loadings and end conditions, which realize a classical and homogenized expression of the bending response of the shear deformable non-homogeneous FGM beams. Particular solutions for the FGM RBBs under specified end constraints and load conditions are given to validate the theory and methodology. The key merit of this work is to be capable of obtaining the high-accuracy solutions of thick FGM beams in terms of the classical beam theory solutions without dealing with the solution of the complicated coupling differential equations with boundary conditions of the problem.
基金Supported by Beijing Natural Science Foundation, No. 7062064
文摘AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore the pertinent test methods. METHODS: A systematic analysis of 30 probands from HNPCC families in the north of China was performed by immunohistochemistry, microsatellite instability (MSI), gene mutation and methylation detection. RESULTS: High frequency microsatellite instability occurred in 25 probands (83.3%) of HNPCC family. Loss of hMLH1 and hMSH2 protein expression accounted for 88% of all microsatellite instability. Pathogenic muta-tion occurred in 14 samples and 3 novel mutational sites were discovered. Deletion of exons 1-6, 1-7 and 8 of hMSH2 was detected in 3 samples and no large fragment deletion was found in hMLH1. Of the 30 probands, hMLH1 gene promoter methylation occurred in 3 probands. The rate of gene micromutation detection combined with large fragment deletion detection was 46.7%-56.7%. The rate of the two methods in combination with methylation detection was 63.3%. CONCLUSION: Scientific and rational detection strategy can improve the detection rate of HNPCC. Based on traditional molecular genetics and combined with epigenetics, multiple detection methods can accurately diagnose HNPCC.
基金supported by the National Natural Science Foundation of China(Grant Nos.31771415 and 31801054)the Bureau of Science and Technology of Yunnan Province,China(Grant No.2015FA026)+1 种基金the Youth Innovation Promotion Association,Chinese Academy of Sciencesthe support of the CAS-TWAS President’s Fellowship Program for Doctoral Candidates。
文摘Piao chicken,a rare Chinese native poultry breed,lacks primary tail structures,such as pygostyle,caudal vertebra,uropygial gland,and tail feathers.So far,the molecular mechanisms underlying tail absence in this breed remain unclear.In this study,we comprehensively employed comparative transcriptomic and genomic analyses to unravel potential genetic underpinnings of rumplessness in Piao chicken.Our results reveal many biological factors involved in tail development and several genomic regions under strong positive selection in this breed.These regions contain candidate genes associated with rumplessness,including Irx4,Il18,Hspb2,and Cryab.Retrieval of quantitative trait loci(QTL)and gene functions implies that rumplessness might be consciously or unconsciously selected along with the high-yield traits in Piao chicken.We hypothesize that strong selection pressures on regulatory elements might lead to changes in gene activity in mesenchymal stem cells of the tail bud.The ectopic activity could eventually result in tail truncation by impeding differentiation and proliferation of the stem cells.Our study provides fundamental insights into early initiation and genetic basis of the rumpless phenotype in Piao chicken.
